Saw Blade Stability And Collet System Mechanism

ABSTRACT

A surgical system for cutting tissue of a patient includes an outer housing and a reciprocating assembly structurally configured to carry a cutting tool in a reciprocating motion. An actuator knob is manually accessible to the user and may be fixed axially to the outer housing. The reciprocating assembly may reciprocate relative to the actuator knob. The actuator knob may be configured for rotational movement between a lock position and an unlock position. The system may also include a locking mechanism configured to retain a cutting tool within the reciprocating assembly. The locking mechanism may be responsive to movement of the actuator knob to maintain the tool within the output shaft when the actuator knob is in the lock position and permit removal of the tool when the actuator knob is in the unlock position. Surgical cutting tools, such as blades include thickness enhancing features.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/366,621 filed on Feb. 6, 2012. The entire disclosure of the aboveapplication is incorporated herein by reference.

FIELD

This disclosure is directed to a surgical system for cutting tissue andmore particularly, to a blade stability and collet mechanism for asurgical saw and associated blades for cutting bone and tissue.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Surgical saw blades of varying sizes, shapes and thicknesses areinserted and removed from surgical saws prior to, sometimes during, andafter surgical procedures and must be retained securely to the saw'sreciprocating shaft. The variety of available blade types and sizespresent challenges that must be overcome to maintain stability of theinterface for all blade options as well as to maintain user simplicityfor improved operational effectiveness. The saws are often arranged sothat the saw blades project axially from the distal end of the saw witha blade retention post or driver positioned laterally within the saw. Toaccommodate the post, some blades have openings or gaps formed intotheir proximal ends. For operator simplicity, a saw design is oftencreated to allow use of the various blade embodiments. However, whenblades of differing geometry are used (thinner for example), thestability of the saw interface may not be as desirable as with thickerblades due to the increased clearances unless considerations are made inthe design of the saw, blade or both. Further, the flexible design mustbe simple for the user to operate to minimize confusion and improveefficiency in the potentially busy environment of an operating room.

The present disclosure is directed to a surgical system including ablade retention mechanism and a saw blade addressing one or more of thelimitations in the prior art.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In one exemplary aspect the present disclosure is directed to a surgicalsystem for cutting bone and tissue of a patient. It includes an outerhousing and a reciprocating assembly disposed in the outer housing. Thereciprocating assembly may be structurally configured to carry a cuttingtool in a reciprocating motion, and may have a tool receiving openingformed therein. An actuator knob is manually accessible to the user andmay be fixed axially to the outer housing. The reciprocating assemblymay reciprocate relative to the actuator knob. The actuator knob may beconfigured for rotational movement between a lock position and an unlockposition. The system may also include a locking mechanism configured toretain a cutting tool within the reciprocating assembly. The lockingmechanism may be responsive to movement of the actuator knob to maintainthe tool within the output shaft when the actuator knob is in the lockposition and permit removal of the tool when the actuator knob is in theunlock position.

In one aspect, the locking mechanism comprises a lock pin associatedwith the reciprocating assembly. The lock pin may be moveable in adirection transverse to the direction of the reciprocating motion whenthe actuator knob rotates between a lock position and an unlockposition. In one aspect, the actuator knob comprises an inner camsurface configured to engage and displace the lock pin upon rotation ofthe actuator knob.

In another exemplary aspect the present disclosure is directed to asurgical system for cutting bone and tissue of a patient. The systemincludes a outer housing and a reciprocating assembly disposed in theouter housing. The reciprocating assembly may be structurally configuredto carry a cutting tool in a reciprocating motion. The reciprocatingassembly may have a tool receiving opening formed therein, and maycomprise a locking mechanism configured to retain a cutting tool withinthe output shaft. The locking mechanism may be displaceable in adirection transverse to the direction of the reciprocating motion andmay be structurally configured to engage the tool in a first positionand to be disengaged from the tool in a second position. An actuatorknob may be manually accessible to the user and may be disposed aboutthe reciprocating assembly. The actuator knob may be fixed axially tothe housing and may be rotatable relative to the housing. It may have aninner cam surface configured to selectively engage the locking mechanismand displace the locking mechanism from the first position to the secondposition. The inner cam surface may extend axially in the longitudinaldirection to accommodate the reciprocating motion of the lockingmechanism.

In one aspect, the locking mechanism includes a lock pin having a firstportion configured to engage with the inner cam surface of the actuatorknob, a second portion configured to engage a side of a cutting tooldisposed within the tool receiving opening of the reciprocatingassembly, and a neck portion disposed between the first and secondportions. The neck portion may have a transverse width smaller than atransverse width of the second portion to permit insertion, retentionand removal of the tool.

In another exemplary aspect, the present disclosure is directed to asurgical cutting blade for cutting bone material when the blade iscoupled to a hand-held surgical saw. The cutting blade may include adistal portion comprising a plurality of cutting teeth, a proximalportion disposed opposite the distal portion shaped to attach to thesurgical saw and being formed of a material having an upper surface andan opposing lower surface, the material having a first thickness. Inaddition, the blade may include intermittent thickness enhancingfeatures on the proximal portion. The thickness enhancing features mayhave a high point offset from the upper surface and a low point offsetfrom the lower surface of the material, the distance between the highpoint and low point forming a second thickness greater than the firstthickness.

In one aspect, the intermittent thickness enhancing features comprisesdeformed portions formed by bends in the material. In another aspect,the deformed portions are at least one of embossments, extendingfingers, and molded material. In one aspect, the intermittent thicknessenhancing features are formed along lateral edges of the proximalportion.

In another exemplary aspect, the present disclosure is directed to asurgical cutting blade for cutting bone material when the blade iscoupled to a hand-held surgical saw. The cutting blade may include afirst surface comprising a first substantially planar surface portionand a first deformed surface portion. It may also include a secondsurface comprising a second substantially planar surface portionparallel to the first substantially planar surface portion and a seconddeformed surface portion. The distance between the first substantiallyplanar surface portion and the second substantially planar surfaceportion may define a first thickness. The first deformed surface portionmay have a first peak surface point offset from the first substantiallyplanar surface, where the distance between the first peak surface pointand the second surface define a second thickness greater than the firstthickness. A plurality of cutting teeth may be disposed at an edge ofthe first and second planar surfaces.

In one aspect, the second deformed surface portion has a second peaksurface point offset from the second substantially planar surface, andthe distance between the first peak surface point and the second peaksurface point defines the second thickness greater than the firstthickness. In one aspect, the blade includes a distal portion includingthe plurality of cutting teeth, a proximal portion, and shank betweenthe distal and proximal portions. The proximal portion may comprise boththe first and second substantially planar surface portions and the firstand second deformed surface portions.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an illustration of an exemplary reciprocating bone-cuttingsurgical system according to one exemplary aspect of the presentdisclosure.

FIG. 2 is an illustration of a longitudinal cross-section of thereciprocating bone-cutting surgical system of FIG. 1 according to oneexemplary aspect of the present disclosure.

FIG. 3 is an illustration of an exemplary cutting tool from thereciprocating bone-cutting surgical system of FIG. 1 according to oneexemplary aspect of the present disclosure.

FIG. 4 is an illustration of an exploded blade retaining mechanism fromthe reciprocating bone-cutting surgical system of FIG. 1 according toone exemplary aspect of the present disclosure.

FIG. 5 is an illustration of a traverse cross-section of a portion ofthe blade retaining mechanism of the reciprocating bone-cutting surgicalsystem of FIG. 1 according to one exemplary aspect of the presentdisclosure.

FIGS. 6 and 7 are partial cross-sectional views showing a portion of theblade retaining mechanism of the reciprocating bone-cutting surgicalsystem of FIG. 1 according to one exemplary aspect of the presentdisclosure.

FIG. 8 is an illustration of a longitudinal cross-section of thereciprocating bone-cutting surgical system of FIG. 1 in a retractedcondition according to one exemplary aspect of the present disclosure.

FIG. 9 is an illustration of an exemplary cutting tool set usable with asurgical saw of the reciprocating bone-cutting surgical system of FIG. 1according to one exemplary aspect of the present disclosure.

FIG. 10 is an illustration of a proximal portion of the cutting tools ofFIG. 9 according to one exemplary aspect of the present disclosure.

FIGS. 11-12 are illustrations of another embodiment of a proximalportion of an additional cutting tool according to one exemplary aspectof the present disclosure.

FIGS. 13-14 are illustrations of another embodiment of a proximalportion of an additional cutting tool according to one exemplary aspectof the present disclosure.

FIG. 15 is an illustration of another embodiment of a proximal portionof an additional cutting tool according to one exemplary aspect of thepresent disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Generally, the present disclosure relates to a bone cutting surgicalsystem including a hand-held, high-speed, bone-cutting surgical saw anda cutting tool shown as a cutting saw blade. The surgical saw includes amechanism that uniquely retains the cutting tool. In one aspect, itincludes an intuitive quarter-turn actuator knob that isnon-reciprocating. Because the actuator knob is non-reciprocating, itmay shield users from inadvertent contact with the reciprocating portionof the saw. In addition, the quarter-turn knob may simplify the userinteraction required to attach a cutting tool, which may providebenefits in a fast-paced environment of an operating room. Thereciprocating saw shaft is arranged to accept both flat and shaftedcutting tool shanks in varying thickness ranges. For thinner blades,thickness enhancing features such as one or more deformations or otherfeatures, are incorporated providing identical stability inherent withthicker flat blades.

Turning now to FIG. 1, the present disclosure is directed to abone-cutting surgical system 100 including a hand-held surgical saw 102and a selectively removable micro-cutting tool 104, shown as a sawblade. The surgical saw 102 includes a hand-piece 106, a cord 108extending from a proximal end, and a blade retaining mechanism 110disposed at its distal end. The handpiece 106, in this example, isdivided into a motor housing 112 and a drive housing 114. The motorhousing 112 carries the motor that drives the reciprocating action ofthe cutting tool 104. The drive housing 114 carries the components thattransform the rotating motor output to reciprocating motion and thatdrives the cutting tool 104. In one example, the cord 108 extends to aseparate console (not shown) and may be permanently coupled or removablycoupled to the power source. Additional contemplated embodiments includea power source as a part of the hand-piece 106, such as a batterypowered hand-piece. In one example, the surgical saw is a pneumaticallydriven saw.

FIG. 2 is an enlarged cutaway, cross-sectional view of the drive housing114 of the handpiece 106 and the blade relating mechanism 110, with thecutting tool 104. The drive housing 114, according to an exemplaryembodiment, includes a bevel pinion 118, an eccentric crank assembly120, a yoke 122, and an output shaft assembly 124. The bevel pinion 118includes a gear shaft 126 and a gear head 128. The gear shaft 126 iscarried by bearings 130 in a bearing housing 132 disposed in the drivehousing 114. The gear shaft 126 extends proximally and is configured toattach to a drive shaft of the motor (not shown) disposed in the motorhousing 112 (FIG. 1).

The eccentric crank assembly 120 includes a bevel gear 136, a crank axle138, bearings 140, and a crank arm 142. The bevel gear 136 mates withthe gear head 128 of the bevel gear 118. The crank axle 138 isrotationally fixed to the bevel gear 136 so that rotation of the bevelgear results in rotation of the crank axle 138. The bearings 140 supportends of the crank axle 138 and maintain it in position. The crank axle138 includes an eccentric portion 144, and the crank arm 142 extendsfrom the crank axle 138. In use, the motor output shaft drives the gearshaft 126 of the bevel pinion 118. Rotation of the bevel pinion 118rotates the bevel gear 136, converting the rotation about thelongitudinal axis of the saw 102 to rotation about an axis transverse tothe longitudinal axis. The bevel gear 136 drives the crank axle 138. Asthe crank axle 138 turns, the eccentric portion 144 rotates about thetransverse axis. The crank arm 142, rotationally attached to theeccentric crank and is then reciprocated in a direction along thelongitudinal axis.

The yoke 122 is connected to the crank arm 142 by a transverselyextending connector pin 146. The yoke 122 includes a hollow longitudinalchamber 147 extending from a distal end 148 to a proximal end 149. Theproximal end 149 is formed to receive the pin 146, which is rotatablerelative to one or both of the crank arm 142 and the yoke 122. The yoke122 is disposed within a linear bearing 150 carried in the drive housing114. The linear bearing 150 includes a liner 152 fit within the drivehousing 114 that carries a liner cage 154 and ball bearings 156. As thecrank arm 142 moves in a reciprocating motion, the yoke 122 reciprocatesin the linear bearing 150.

The output shaft assembly 124 includes an output shaft 160, a connector162 connecting the output shaft 160 to the yoke 122, and a retainingsleeve 164 disposed about a portion of the output shaft 160. The outputshaft 160 includes a proximal portion 166 and a distal portion 168. Inthe example shown, the proximal portion 166 includes a hollow receivingchamber 170 formed as a blind bore 172 with a countersink portion 174.The countersink portion 174 is configured to receive and interface witha distal end of the yoke 122. In one embodiment, these are press-fittogether. The blind bore 172 receives the distal end 148 of the yoke122. In this example, the blind bore portion of the receiving chamber170 is threaded. In this example, a connector 162 extends from insidethe hollow chamber 147 of the yoke 122 to connect with the output shaft160, thereby fixedly securing them together. In this example, theconnector 162 is a fastening bolt that extends from a location insidethe hollow chamber 147 to the blind bore 172, and threads into the blindbore 172 to connect the output shaft 160 and the yoke 122. Thus,reciprocating movement of the yoke 122 results in reciprocating movementof the output shaft 160.

The distal portion 168 of the output shaft 160 includes a tool receivingopening 180 extending longitudinally into the saw 102. The toolreceiving opening 180 is sized and configured to receive a cutting toolusable in a surgical procedure. In this example, the tool receivingopening 180 is sized and configured to receive the cutting tool 104. Thetool receiving opening 180 in this embodiment is configured to receiveeither a flat shank of a cutting tool or a cylindrical shank of acutting tool. To do this, the output shaft 160 has a central cylindricalbore 182 sized to receive and hold a cylindrical shaft of a cuttingtool. In addition to the central cylindrical bore 182, the output shaft160 includes two longitudinal slots 184 (not visible in FIG. 2) onopposing sides of the bore 182 that carry the cutting tool 104. Theslots 184 can be seen particularly well in the cross-section of FIG. 5.These slots 184 are sized to receive a flat shank of a cutting tool,such as the cutting tool 104, that has a width greater than the diameterof the central cylindrical bore 182. Accordingly, the surgical saw 102is configured to receive either type of tool without requiringinterchanging of receiving components. This makes the surgical saw 100compatible with a greater number of tools, simplifying tool changeoverand resulting in fewer required tools in the surgical room. In theembodiment shown, the slots 184 extend in the proximal direction furtherthan the cylindrical bore 182.

The output shaft 160 includes a transverse hole 186 configured toreceive a portion of the blade retaining mechanism 110. The transversehole 186 extends more than half-way through the output shaft diameterand through the slots 184.

The retaining sleeve 164 is disposed about the distal portion 168 of theoutput shaft 160. It does not cover the transverse hole 186 for reasonsthat will become apparent below. Since the slots 184 extend to the outercircumference of the output shaft, the retaining sleeve 164 serves as aboundary that limits the overall width of the cutting tool size that canbe inserted into the slots 184. In addition, it limits transversedisplacement and reacts transverse loading on flat cutting tools, suchas blades. Transverse loading of tools with a cylindrical shank arereacted by the bore 182. The retaining sleeve 164 is laser welded orotherwise attached to the output shaft 160 to effectively operate as asingle, integral unit. Additional features of the retaining sleeve 164are described further below with reference to FIG. 4.

For ease of explanation, the cutting tool 104 will be described beforecontinuing with the description of the surgical saw. FIG. 3 shows anexemplary cutting tool 104 usable with the surgical saw 102 in FIG. 1and securable with the blade retaining mechanism 110. Here, the cuttingtool is formed of a single, monolithic material that may be stamped orcut from a metal sheet or flat material. As such, the cutting toolcomprises two planar, parallel sides. The cutting tool 104 includes aproximal portion 300 that that facilitates interconnection with theblade retaining mechanism 110 and a distal portion 302 having a cuttingedge 304 including a plurality of cutting teeth 306 formed thereon. Inthis example, the cutting edge 304 is disposed along a lateral side ofthe cutting tool 104.

In this example, the proximal portion 300 is defined by a shank 310 thatincludes a slot 312 extending inwardly along a longitudinal axis 314from the proximal portion 300 of the cutting tool 104. The slot 312divides the proximal portion 300 into two parallel,proximally-projecting arms 311. As shown, the slot 312 is shaped askey-hole with a wider portion 316 and a narrower portion 318. In thisembodiment, the narrower portion 318 is proximal of the distal widerportion 316. Here, the wider portion 316 is circular shaped, while thenarrower portion intersects the circular shape with substantiallystraight longitudinal edges. The transverse distance d2 measured betweenthe longitudinal edges is less than the distance d1 of the circularportion as shown in FIG. 8. The narrower portion extends substantiallyto a proximal end 320 of the cutting tool 104. In the example shown, thenarrower portion 318 intersects with the proximal end 320 of the cuttingtool at a funnel-like opening 322 defined by substantially straightedges 318 facing at angle toward the longitudinal axis 314. The straightedges may help guide the cutting tool 104 into place on the bladeretaining mechanism 110.

Returning now to the surgical saw, the blade retaining mechanism 110will now be described. The blade retaining mechanism 110 is configuredto connect the cutting tool 104 to the surgical saw 102 simply andsecurely, while shielding reciprocating elements from the user. Theblade retaining mechanism 110 is shown in FIG. 4 in exploded form. Itincludes the output shaft 160 with the retaining sleeve 164, a lockingmechanism 200, an actuator knob 202, a cap 204, and a stop pin 206. FIG.4 shows the transverse hole 186 in the output shaft 160. Adjacent thetransverse hole 186, the output shaft 160 includes a pin-hole 188 thatintersects the transverse hole 186.

As can be seen, the output shaft 160, with the retaining sleeve 164disposed about its distal end, projects from the drive housing 114. Theretaining sleeve 164 in this example includes two opposing projectingportions 190 (only one is shown in FIG. 4) configured to be receivedinto corresponding slots 192 (only one is shown in FIG. 4) in the outputshaft 160. Here, the slots 192 align radially with the slots 184 formedin the output shaft 160.

The locking mechanism 200 is disposable in the transverse hole 186 andincludes a lock pin 210, a lock spring 212, and a pin stop 214. The lockpin 210 is configured to displace relative to the transverse hole 186.It is also shown in cross-section in FIG. 5. The lock pin 210 includes around upper portion 220, a neck 222, and a lower portion 224. The upperportion 220 includes rounded top engagement surface 221 and a throughslot 226 extending therethrough that receives the pin stop 214.

The neck 222 is a narrow portion between the upper and lower portions220, 224. In the embodiment shown, it has a circular diameter. However,in some embodiments, the neck 222 is narrow on only two transversesides. The neck 222 is sized to fit between the parallel projecting arms311 on the cutting tool 104 or on other surgical tools. As such, it hasa diameter or transverse width less than the width d2 in FIG. 3.Therefore, when the neck 222 is aligned with the slots 184 in the outputshaft 160 (when the actuator knob is rotated to the unlocked position),the cutting tool 104 may be inserted and removed from the surgical saw102 because the projecting arms 311 of the cutting tool can slide paston either side of the neck 222.

The lower portion 224 includes a first tier 230 having a first diameterand a second tier 232 having a second diameter. The diameter (or width)of the first tier 230 is sized to correspond with the wider portion 316of the cutting tool 104 in FIG. 3. Accordingly, the diameter (or width)of the first tier 230 is greater than the distance d2 in FIG. 3. As canbe seen in FIG. 4, the first tier 230 is disposed between the projectingarms 311 of the cutting tool 104. The second tier 232 has a diameter orwidth sized larger than the wider portion 316 between the parallelprojecting arms 311 on the cutting tool 104. This can be seen in FIG. 5,where the second tier 232 is configured to abut against, but not passbetween the two projecting arms 311 on the cutting tool 104. The lowerportion 224 also includes a receiving bore 234 formed therein thatreceives the lock spring 212. The lock spring 212 also engages thebottom of the transverse hole 186 and provides a biasing force to biasthe lock pin 210 to a tool locked position in the output shaft 160.Here, the tool lock position is where the first tier 230 is disposed inthe wider portion 316 of the cutting tool. The tool unlock position iswhere the neck 222 is disposed in the wider portion 316 of the cuttingtool 104. In FIG. 5, the cutting tool 104 is in the tool lock positionbecause the first tier 230 of the bottom portion 224 is disposed betweenthe projecting arms 311 of the cutting tool 104 preventing its removal.Because the first tier width is greater than the distance d2, the firsttier 230 mechanically prevents removal of the cutting tool 104. Inaddition, since the lateral edges of the cutting tool 104 extend intothe slots 184 on each side of the transverse hole 186, the arms 311 ofthe cutting tool are trapped between the boundary of the slots 184 andthe second tier 232, biased against the cutting tool 104.

In FIG. 5, the pin stop 214 extends through the through slot 226 in thelock pin 210, and into the output shaft 160. Since it is secured inplace in the pin hole 188 (FIG. 4), the lock pin 210 may move up anddown within the transverse hole 186, but cannot be removed from thetransverse hole 186. That is, the pin stop 214 limits the range of thetravel of the lock pin 210, preventing its removal from the transversehole 186. As can be seen the lock spring 212 biases the lockpin 210toward a locked position.

The actuator knob 202 will be described with reference to FIGS. 2 and4-7. The actuator knob 202 is rotatable relative to the drive housing114 about the longitudinal axis, and is used to change the surgical sawbetween a tool lock position and a tool unlocked position, or a releaseposition. In the tool lock position, the cutting tool 104 is secured inthe surgical saw 102 and cannot be removed. In the tool unlock position,the cutting tool 104 may be removed from or a new tool may be insertedinto the surgical saw 102. In this embodiment, the actuator knob 202 isaxially fixed relative to the drive housing 114 and does not move withthe reciprocating elements of the surgical saw 102. Accordingly, theactuator knob 202 may shield users or the patient from inadvertentcontact with reciprocating elements of the surgical saw 102, such as theoutput shaft 160.

The actuator knob 202 has a distal portion 236 and a proximal portion238. An outer surface 240 includes gripping features 242, shown as aseries of longitudinally extending indentations. In addition, the outersurface 240 includes reference indicia 241 disposed to mark the relativeposition of the actuator knob 202 and indicate whether the bladeretaining mechanism 110 is in a locked or unlocked condition.

The proximal portion 238 of the actuator knob 202 includes a flange 244extending, in this embodiment, three quarters or 270 degrees about theactuator knob 202. Accordingly, in this embodiment, the flange 244includes a 90 degree cutout 246 in the flange 244. The edges of theflange 244 at the cutout 246 define stop surfaces 248, as will bedescribed further below.

A radial recess 250 adjacent the flange 244 includes pockets 252operable as a portion of a detent that provides users with tactilefeedback when rotating the actuator knob 202. In this embodiment, theactuator knob 202 includes four pockets 252 that cooperate with detentballs (not shown) disposed in the drive housing 114 in a manner known inthe art. In addition to the pockets 252, the radial recess 250 includesone or more windows 254 that aid in the communication of steam passagesduring the steam sterilization processes.

The actuator knob 202 has an inner passage formed by two portions. Ascan be seen in FIG. 2, the distal portion 236 of the actuator knob 202includes a substantially cylindrical inner surface 255, while theproximal portion 238 of the actuator knob 202 includes a cam-shapedinterior surface 256. A cross-section of the cam-shaped interior surface256 is shown in FIG. 5. The cam shaped interior surface 256 isconfigured to interface with the engagement surface 221 of the lock pin210. Since the actuator knob can 202 be rotated about the longitudinalaxis, the cam surface 256 can rotate relative to the drive shaft 160,and the corresponding locking mechanism 200. Its rotation causes aportion of the inner surface of the cam surface 256 to engage againstand radially displace the lock pin 210 deeper into the transverse hole186, compressing the lock spring 212. This displacement moves thelockpin 210 from its locked position with the lower portion 224 engagingor otherwise preventing removal a cutting tool 104 to its unlockedposition, where the neck 222 is aligned with the slots 184 and thecutting tool 184 can be inserted or removed. FIG. 5 shows the camsurface aligned in the locked position, where the lock pin 210 is ableto project from the output shaft 160 and the lower portion 224 of thelock pin 210 is engaged with the cutting tool 104.

The cap 204 is best seen in FIGS. 4, 6, and 7 and is configured toconnect to and be fixed in place relative to the drive housing 114. Inthe example shown, the cap 204 includes a rounded distal end and aproximal portion that projects into the drive housing 114. As best seenin FIG. 4, the cap 204 includes a pin receiving slot 270 formed in oneside. The pin receiving slot 270 is disposed radially inward from theexterior of the cap 204, so that the stop pin 206, shown as a pin, inthe receiving slot 270 can be retained inside the cap 204 and the drivehousing 114. In this example, the cap 204 has an outer diameter sized tomatch that of the drive housing 114. In this example, a first referenceindicium shown as a lock indicium 272 representing a locked position anda second reference indicium shown as an unlock indicium 274 representingan unlocked condition are disposed on the outer surface of the cap 204.These reference indicia are disposed to correspond to a position of theactuator knob 202 with its indicium 241 and indicate whether the bladeretaining mechanism 110 is in a locked or unlocked condition. In thisexample, the reference indicia 272, 274 are spaced 90 degrees apart,indicating that the actuator knob 202 is a quarter-turn (90 degree turn)element to change from the locked position to the unlocked position orthe unlocked position to the locked position.

Still referring to FIGS. 2 and 4, the surgical saw 102 includes a lipseal 280 and an o-ring 282. The lip seal 280 is disposed in contact withthe drive shaft 160, and the o-ring 282 is disposed in contact with theactuator knob 202.

The stop pin 206, shown in FIG. 4, is disposed in the pin receiving slot270 in the cap 204 and in the drive housing 114. The stop pin 206 isaligned adjacent the actuator knob 202, and extends through the cutout246. When the actuator knob 202 is rotated, the flange ends 248 adjacentthe cutout 246 engages the stop pin 206 and mechanically preventsadditional rotation of the actuator knob 202. Accordingly the cutout 246is aligned with the stop pin 206 so that the rotation of the actuatorknob 202 occurs between the locked and unlocked position.

In the example shown, the cutout 246, the indicia 241, and the camsurface 256 are all configured so that the locked condition and theunlocked condition are a quarter turn or 90 degrees apart. However, inother examples, the range of rotation is selected to be different than90 degrees. In one example the range of rotation is greater than 90degrees, and in one embodiment is within a range of 190 and 110 degrees.Other ranges, both larger and smaller are contemplated and can bearranged by adjustment of the flange cutout 246, the inner cam surface256, and other components.

FIG. 6 shows a partial cross-sectional view of the blade retainingmechanism 110 in an unlocked position without a cutting tool, and FIG. 7shows the blade retaining mechanism 110 in a locked position with thecutting tool 104. As can be seen in FIG. 6, the marking indicium 241 onthe actuator knob 202 is aligned with the unlock indicia 274 on the cap204. As such, the actuator knob 202 is rotated so that the cammed innersurface 256 is engaged with the engagement surface 221 of the upperportion 220 of the lock pin 210, and the lockpin 210 is pressed into thetransverse hole 186. This aligns the neck 222 with the slots 184 so thata cutting tool introduced into the tool receiving opening 180 canadvance past the narrow neck 222. With the cutting tool inserted beyondthe neck 222, the actuator knob 202 may be rotated from the unlockedposition in FIG. 6 to the locked position in FIG. 7.

FIG. 7 shows the marking indicium 241 on the actuator knob 202 alignedwith the unlock indicium 274 on the cap 204. As such, the actuator knob202 is rotated so that the cammed inner surface 256 is spaced away fromthe engagement surface 221 of the upper portion 220 of the lock pin 210.As this occurs, the lock spring (FIG. 2) displaces the lockpin 210 fromthe depressed position to a position where the lower portion 224 engagesthe cutting tool 104. In this example, the first tier 230 of the lowerportion 224 extends into the wider portion 316 of the slot 312 in thecutting tool 104 and the second tier 232 engages and contacts the bottomsurface of the cutting tool 104. The first tier 230 prevents removal ofthe cutting tool 104 from the surgical saw 102 as explained above. Here,only the distal end portion of the cam surface 256 is shown in FIG. 7.However, as shown in FIG. 2, the cam surface 256 extends proximally.This ensures that even while the output shaft 160 reciprocates with theprotruding lock pin 210 extending up out of the transverse hole 186, thelock pin 210 is not inadvertently displaced in a manner that willrelease the cutting tool.

FIG. 8 is a cross-sectional view similar to FIG. 2 with the componentsof the surgical saw 102 in a retracted position during a reciprocatingcycle. As can be seen, the output shaft 160 reciprocates in a forwardand rearward direction relative to the actuator knob 202. The retainingsleeve 164, which is fixedly connected to the yoke 122 alsoreciprocates. However, in this example, the components manipulated bythe user, such as the actuator knob 202 do not reciprocate. Because ofthis, the actuator knob 202 may shield the surgeon and the patient fromthe reciprocating output shaft 160. In addition, by forming thereciprocating knob 202 and the mating features of the retainingcomponents to be axially fixed relative to the drive housing 114, themass of the reciprocating portion is reduced. This may reduce vibrationduring operation, resulting in improved ergonomics for the surgeon.

FIG. 9 shows an exemplary tool set 400 having a plurality of cuttingblades shown as saw blades usable with the blade retaining mechanism 110disclosed herein. Here, the tool set 400 includes blades 402, 404, 104,and 406. The cutting tool 104 was described above with reference to FIG.3. For ease of explanation, blade features similar to those of cuttingtool 104 will be described with similar reference numbers. Further, somefeatures, such as the distal portion and the teeth will not be furtherdescribed here. Each of blades 402, 404, 406, like cutting tool 104, hasa proximal portion 300 that that facilitates interconnection with theblade retaining mechanism 110. The proximal portion 300 is includes theslot 312 extending inwardly from the proximal end of the cutting tool402, 404, 406. The slot 312 divides the proximal portion 300 into twoparallel, proximally-projecting arms 311. In the embodiments shown, theslot 312 is shaped as key-hole with a wider portion 316 and a narrowerportion 318. The transverse distance d2 measured between thelongitudinal edges is less than the distance d1 of the circular portionas shown in FIG. 8. The narrower portion extends substantially to aproximal end 320 of the cutting tool 104. In the example shown, thenarrower portion 318 intersects with the proximal end 320 of the cuttingtool at a funnel-like opening 322.

In this blade set 400 however, the thickness of the blades of the toolset 400 varies across blades. FIG. 10 shows the proximal portions 300 ofthe plurality of blades 400 for simple comparison. Each of the tools402, 404, 104, 406 includes an upper facing flat surface 412 and a lowerfacing flat surface 414. In this example, the blade 402 includes has ablade thickness Z measured between the flat surfaces 412, 414, the blade404 has a blade thickness Y, the blade 104 has a blade thickness X, andthe blade 406 includes a cylindrical shank 410 that ends in a flat bladehaving a blade thickness W. Cylindrical shank type tools may beavailable in varying blade thickness for surgeon preference with respectto kerf width, flexibility, etc. In this example, the blade thickness Xis selected to fit within the tool receiving opening 180 and slide alongthe slots 184 with the most desirable fit. That is, the thickness X isselected to have a desired level of clearance in the slots for bladechange-over, while at the same time minimizing the amount of excessclearance between blade 104, 402, 404, 406 and shaft 160. Minimizingexcess clearance may result in less undesirable blade movement duringcutting, resulting in a cleaner more accurate cut. This in turn resultsin a better patient outcome.

Each of the blades 104, 402, 404, 406 having a particular thickness maybe utilized during different aspects of a procedure or may havedifferent advantages or disadvantage for a particular surgical techniqueor procedure. However, in order to obtain consistency by minimizingundesirable blade movement, the blade shanks in each of the blades 402,404, and 406 are deformed to create an effective thickness that matchesthe thickness X.

In the example shown, for example, although blade 402 has a thickness Zmeasured between the flat upper surface and the flat lower surface, thelateral edges of the shank 412 include a plurality of intermittentthickness enhancing features 420 shown as a deformed portion thatresults in a thickness X. For example, the deformed portion may comprisea plurality of embossments 422 alternating between peak high points 424creating a point of greatest elevation from the upper flat surface 412and a peak low point 426 of lowest elevation from the lower flat surface414, where the distance between the high point 424 and the low points426 match the thickness X. In the example shown the embossments 422 forma wave shape that appears as a sinusoidal embossment. The embossments422 are formed by bending the material. This may be accomplished using,for example, a stamping or a forging process. Other processes also maybe used.

Blades 402 and 406 are similarly deformed to provide an effectivethickness X to correspond with a desired blade thickness for the bladeretaining mechanism 110. While shown with embossments only on thelateral edges of the shank, the embossments in some embodiments extendlaterally across the shank. In addition as can be seen, each of theblades 402, 404, and 406 have embossments or deformations proximal ofthe distal end of the slot 312. In examples where the embossments extendlaterally across the shank, the flat surfaces are defined by the distalend of the cutting tools, where the cutting blade has flat parallelsides.

The cylindrical shank 410 of cutting tool 406 is compatible with thesurgical saw 102 by virtue of the cylindrical bore 182 in the outputshaft 160. In addition, since the proximal portion 300 is flat, thecutting tool 406 also is compatible with the remaining components of theblade retaining mechanism 110, and may be maintained in the surgical sawby the locking mechanism 200.

FIGS. 11-15 show alternative intermittent thickness enhancing features.FIGS. 11 and 12 show a cutting tool 450 with deformed portions ofalternating upper stamped fingers and lower stamped fingers 452. Thealternating high points 424 and low points 426 on the stamped fingers452 match the thickness X as described above. FIGS. 13 and 14 show a sawblade 470 with alternating embossed dimples 472 where the high points424 and the low points 426 on the dimples 472 match the thickness X.FIG. 15 shows a side view of a cutting tool 490 with molded bumps 492where the high points 424 and low points 426 on the molded bumps 492match the thickness X. This embodiment includes a plurality of throughholes 494 on the shank of the cutting tool 490. The molding materialextends through the holes 494 to form the bumps 492 on both sides of thecutting tool 490, giving it a desired effective thickness. In anotherembodiment, the intermittent thickness enhancing features are laminatedsegments, such as laminated flat sections disposed on the proximalportions of the blades.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A surgical cutting blade for cutting bonematerial when the blade is coupled to a hand-held surgical saw, thecutting blade comprising: a distal portion comprising a plurality ofcutting teeth; a proximal portion disposed opposite the distal portion,the proximal portion being shaped to attach to the surgical saw andbeing formed of a material having an upper surface and an opposing lowersurface, the material having a first thickness; and intermittentthickness enhancing features on the proximal portion, the thicknessenhancing features having a high point offset from the upper surface anda low point offset from the lower surface of the material, the distancebetween the high point and low point forming a second thickness greaterthan the first thickness.
 2. The cutting blade of claim 1, wherein theintermittent thickness enhancing features comprises deformed portionsformed by bends in the material.
 3. The cutting blade of claim 1,wherein the intermittent thickness enhancing features are at least oneof embossments, extending fingers, laminated portions, and moldedmaterial.
 4. The cutting blade of claim 2, wherein the deformed portionsare one of sinusoidal waves and bumps.
 5. The cutting blade of claim 1,wherein the intermittent thickness enhancing features are formed alonglateral portions of the proximal portion.
 6. The cutting blade of claim1, wherein the proximal portion comprises through holes formed therein,the intermittent thickness enhancing features comprising a moldedmaterial extending through the through holes and forming a thicknessenhancing feature on the upper surface and forming a thickness enhancingfeature on the lower surface.
 7. The cutting blade of claim 1, whereinthe proximal portion of the cutting blade defines a slot extending fromthe proximal portion toward the distal portion, wherein the slot isshaped as a key hole with a wider distal portion and a narrower proximalportion.
 8. The cutting blade of claim 7, wherein the intermittentthickness enhancing features are proximal a distal end of the slot. 9.The cutting blade of claim 8, wherein the intermittent thicknessenhancing features are distal of the distal end of the slot.
 10. Asurgical cutting blade for cutting bone material when the blade iscoupled to a hand-held surgical saw, the cutting blade comprising: afirst surface comprising a first substantially planar surface portionand a first deformed surface portion; a second surface comprising asecond substantially planar surface portion parallel to the firstsubstantially planar surface portion and a second deformed surfaceportion, the distance between the first substantially planar surfaceportion and the second substantially planar surface portion defining afirst thickness; the first deformed surface portion having a first peaksurface point offset from the first substantially planar surface, thedistance between the first peak surface point and the second surfacedefining a second thickness greater than the first thickness; and aplurality of cutting teeth at an edge of the first and second planarsurfaces.
 11. The surgical cutting blade of claim 10, wherein the seconddeformed surface portion has a second peak surface point offset from thesecond substantially planar surface, the distance between the first peaksurface point and the second peak surface point defining the secondthickness greater than the first thickness.
 12. The cutting blade ofclaim 10, wherein the first and second deformed surface portionscomprise deformed portions formed by bends in the material.
 13. Thecutting blade of claim 10, wherein the first and second deformed surfaceportions are at least one of embossments and extending fingers.
 14. Thecutting blade of claim 10, comprising a distal portion including theplurality of cutting teeth, a proximal portion, and a shank between thedistal and proximal portions, the proximal portion comprising both thefirst and second substantially planar surface portions and the first andsecond deformed surface portions.
 15. The cutting blade of claim 10,wherein the cutting blade defines a proximal slot and the first andsecond deformed surface portions are adjacent the proximal slot.
 16. Aset of surgical cutting blades for cutting bone material when a blade iscoupled to a handheld surgical saw, the set comprising: a first bladeextending from a first proximal portion to a first distal portion andhaving a first proximal thickness between a first upper surface and afirst lower surface; and a second blade extending from a second proximalportion to a second distal portion and having a second proximalthickness between a second upper surface and a second lower surface;wherein the first blade includes a first thickness enhancing featurethat defines a third proximal thickness and the second blade includes asecond thickness enhancing feature that defines a fourth proximalthickness; wherein the first thickness is the same as the secondthickness; wherein the third thickness is greater than the firstthickness and the fourth thickness is greater than the second thickness.17. The set of claim 16, wherein the first and second thicknessenhancing features are formed along lateral portions of the first andsecond proximal portions, respectively.
 18. The set of claim 16, whereinthe first and second thickness enhancing features comprise deformedportions formed by bends in the first and second proximal portions,respectively.
 19. The set of claim 18, wherein the first and secondthickness enhancing features are at least one of embossments, extendingfingers, laminated portions, and molded material.
 20. The set of claim16, wherein the first thickness enhancing feature includes a first highpoint offset from the first upper surface and a first low point offsetfrom the first lower surface, a distance between the first high pointand the first low point forming the third proximal thickness and thesecond thickness enhancing feature includes a second high point offsetfrom the second upper surface and a second low point offset from thesecond lower surface, a distance between the second high point and thesecond low point forming the fourth proximal thickness